Marking systems that transport paper or other media are well known in the art. These marking systems include electrostatic marking systems, non-electrostatic marking systems, printers or any other system where paper or other flexible media or receiving sheets are transported internally to a an output device such as a stacker cart in a finisher and compiler. Many of these machines are used for collecting or gathering printed sheets so that they may be formed into books, pamphlets, forms, sales literature, instruction books and manuals and the like. Often, the loaded stacker cart is emptied or the paper stack unloaded to another surface.
The finisher and compiler are generally located at a site in these marking systems after the receiving sheets (paper) have been toned or marked. A finisher is generally defined as an output device that has various post printer functions or options such as hole punching, corner stapling, edge stapling, sheet and set stacking, letter or tri-folding, Z-Folding, Bi-folding, signature booklet making, set binding [including thermal, tape and perfect binding], trimming, post process sheet insertion, saddle stitching and others. After the paper has been finished or compiled, the paper is transported to a paper cart in a paper stacking housing in the finisher module. From there, this paper stack may be moved to other locations for collection.
The paper after finishing is collected onto a stacker cart that is usually located on a bottom portion of a housing of the finisher module of the printing system. The stacker cart has wheels so that it can be easily rolled out of the lower finisher module housing to some other location or surface. Since the paper stack on the stacker cart is heavy, it needs mechanical or other lifting assistance to lift the stack off the stacker cart in after it leaves the lower housing of the finisher module.
On conventional lift devices, a fixed horizontal platform is used for loading and transporting paper media. While simple in design, the disadvantages of the paper stack accidentally sliding off either while stationary (due to the platform not being exactly level) or while the lift with the load in place is being moved to another station are apparent. The present invention obviates the need for a complicated locking or braking mechanism on either the lift platform or on each plate.